Its Stereo so It won't be playable in Blockland.
1. To make it Mono go to the grey box with its name on it.
2. Click on it
3. It should open up then.
4. Click on split track
5. In each new box click Mono.
6. Click export as ogg
7. A box should come up saying something like 'The new ogg will be morphed into a single track' if it doesn't you messed up.
Hope this works.